ST4000 fluxgate location

[Jim Hardesty]

I'll start off by saying that I did search and found lots of information on locating the fluxgate compass.  They have been mounted a lot of places successfully.  I have always been unhappy with my autopilot being able to hold a good course all the time.  This season I will be single handing a lot more and want better steering from the autopilot.  The original installation had the fluxgate mounted on the crossbeam under the aft water tank just about under the steering pedestal.  One afternoon after adjusting the shaft log I unmounted the fluxgate moved it away and checked the location with my hand held compass.  Got a lot of deviation, so I remounted a bit forward where I got less deviation with my hand held.  It helped some, but it's still not good.  I did recalibrate.
I have a 2001 MKll the autopilot was installed at commissioning.  I am the second owner. The autopilot does work somewhat better when set to the wind function.
After all that, finally my question. 
Would it be worth my effort to relocate the fluxgate compass and where?  By the mast step in the bilge?
Jim

[Steve Sayian]

Jim,

Mine is located in the same space as the holding tank but as far forward as you can go on the inside wall of the tank enclosure. 

Upgraded to a Raymarine Smart Pilot X5 last year and used the same compass that was there for the old ST 4000.  Only problem was setting up the new AP for steering sensitivity.  Once that was done, no problems on holding any course.

Steve

[PK]

Our fluxgate is located in the bilge attached to the mast step, just forward of the mast.  I'm not sure about the deviation or if it is better here than in other locations.  I do know that it occasionally acts up and turns about 30deg to port and then slowly corrects itself to the original heading.  May have something to do with all the wires that run up the mast or some other mystical powers.  Research seems fairly inconclusive on this one.  Not sure if it's due to the location of the fluxgate or some other factor.  Just something to think about.

[Ken Juul]

Do you remember what the deviation setting was in the original site?  According to the manual it should be less than 15°.  If it was within the deviation specifications, then it is something else causing the problem.  The manual also states the flux gate should be near the center of the pitch and roll axis as possible, yet far away from any large metal or other magnetic sources. Perhaps that is the problem. The pitch and roll axis centers are low in the salon.  So the challange is to get the fluxgate as far away from magnetic sources (batteries, electrical panel, battery cables, engine, radar/vhf antenna leads in bilge/mast, etc).  The mast step, by the holding tank, cabin hanging locker, forward of the stbd water tank, etc are the usual choices depending on how your boat is arranged.

Remember if you move it, you will have to do the initial 3 minute circles to recalibrate it.

[Ken Juul]

PK,
Many times the 30° to port is caused by transmitting on the VHF through a mast mounted antenna.

[sail4dale]

I have a 2001 also and after a problem with it mounted in the hanging locker LOW I remounted it about on the level with the chart table.  I felt the low mount picked up interference from the cables under the cabin floor.  IT have been working very well for me for the last 6 years.  OF couirse you nave to be careful of what you puat in the locker that might be magnetic.

[Mike and Joanne Stimmler]

Jim,
I had mine mounter under the seat in the aft cabin on the forward bulkhead and it worked good for me.

Mike

[Fuzzy]

I put mine in the port drawer locker in the  bottom.  It is away from possible flooding in the bilge.  Has worked
perfectly since installing it in 2010.
Larry